After feasibility, produce a principal-engineer design document: resolve all engineering decisions (ADRs, interface contracts, test policy, module boundaries), draft any required ADRs, and route only true product questions back to PM on the meta PRD PR. Runs after /initiative-feasibility on both pass and findings (pin always enters this stage before plan). Writes TDD and Draft ADRs locally (or records N/A / light confirmation when feasibility was clean) and emits Forge readiness for the Draft spec PR; PE accepts architecture in files before planning. Final Gate 2 unlock (spec-lgtm) happens only after the implementation plan exists.
